Table 9.
Effects of parameters on the AM process
| AM process | Parameters | References | |
|---|---|---|---|
| Powder bed fusion | Laser power and scanning speed | A wide range of laser power and scanning speeds can be deemed as optimal; however, a low laser energy density between 50 and 200 J/mm3 is critical. High energy density leads to element vaporisation while low energy density leads to insufficient melting of Mg powder. Energy density is dependent of alloy composition | Chung Ng et al. (2011) |
| Layer thickness | Layer thickness above 250 μm for pure Mg prevented complete fusion and resulted in higher porosity | ||
| Powder size | Magnesium powder of 50 μm for pure Mg was seen to yield better depositions compared to smaller or larger powders. Particles that are too small result in higher rates of vaporisation and particles that are too big do not achieve a full melt | Chung Ng et al. (2011) | |
| Build envelop | The vaporisation temperature of magnesium increases with higher chamber pressures | ||
| Conditions | This facilitates higher operation temperatures for printing Mg. However, safety risks increase by this approach. In addition, preheating of the work table before printing leads to smoother depositions | ||
| Wire arc additive manufacturing | Deposition speed and feed | Higher speeds and feeds of deposition resulted in more refined, smaller grains | uo et al. (2019) |
| Arc frequency | Small refined grains were observed at arcing frequency of 5–10 Hz for TIG WAAM. Grain size was found to increase above and below this frequency range | ||
| Paste extrusion deposition | Extrusion temperature | Flowability of paste was found to increase at higher temperature during extrusion | Farag and Yun (2014) |
| Paste composition | Higher quantities of gelatin in MgP–gelatin mixture resulted in stronger manufactured samples. However, the strength was still much lesser than other sintering or fusion-based AM processes | ||
| Friction stir additive manufacturing | Tool rotational speed | Higher tool force and speeds resulted in higher cladding temperatures, which led to higher porosity in the components | Palanivel et al. (2015) |
| Tool force | Higher tool force increases temperature due to friction, and thus, residual stresses in components increases | ||
| Jetting technologies for additive manufacturing | Binder jetting |
100% recyclability of powder Binding agent must be chosen carefully by considering its reactivity with powder |
Salehi et al. (2019) |
| Binder-less jetting | Prevents contamination due to absence of binding agent |